Did you see the UK isp link in the 1st post here ISP's known to BLOCK or Filter p2p or specifically Limewire

Can you give us more information about your set up. Have you seen this Connection problems? Check here first! (click on link) Your problem might be isp related, it might be software firewall related, it might be modem/router NAT firewall related or a combination. So check these links out to be sure.

If you see a brick wall in front of the blue firewall globe icon at the bottom of LW interface then you can be reasonably sure the 1st place to look for an answer is your firewall be it your software firewall or modem/router (or both.)